How do elephants sleep

Both elephants were followed for five weeks, giving new insights into their natural sleep patterns. Sleep is one of those really unusual mysteries of biology, that along with eating and reproduction, it's one of the biological imperatives. We must sleep to survive. Generally, smaller-bodied mammals sleep for longer than larger ones. For example, sloths sleep for around 14 hours a day, while humans sleep for around 8 hours. How elephants survive on so little sleep remains a mystery.

The researchers are planning follow-up studies on more elephants, including males. They also want to find out more about REM sleep in elephants. REM rapid eye movement sleep is thought to help with the consolidation of memories but further studies in elephants, humans and possible fruit-fly are underway. Many vertebrates yawn in response to witnessing a pack members open-mouthed gape.

This is called intraspecific contagious yawning and not only do African elephants yawn in unison with their herd-mates but like chimpanzees and dogs, they have been recorded yawning in response to a yawn from a different species interspecific contagious yawning , in particular, humans. You can read more about this phenomenon here and here. For now Khanyisa is still spending her sleeping hours in the nursery with Lammie and her blanket as the cold weather creates a need for us to be much more cautious of her health and wellness.

She sleeps like a human baby with interrupted sleeping patterns but the long walks in the wild all day with the herd certainly make her sleep about an hour extra.

On most nights, they slept standing up; on some, they lay down. Of course, Gravett and Manger only studied two elephants, and both were adult matriarchs—the individuals who bear the burden of leading the herd.

The gray whale is much larger than an elephant, but still sleeps for nine hours a day. A dolphin can sleep with one half of its brain at a time, allowing it to stay constantly alert for days at a stretch—but each half still gets at least four daily hours.

Oddly, the next shortest sleeper seems to be the domestic horse, which gets just three hours a day, followed by the domestic pony, which gets slightly more.

For now, it appears that the African savannah elephant is the shortest sleeper around. The longest seems to be the little brown bat, which gets an incredible 19 hours a day. The two tagged individuals were both adult matriarchs who were taking care of young calves, so they may have stayed up all night to avoid harassing lions. Similarly, they might also have been trying to flee from poaches, or bull elephants in heat. Either elephants only experience REM every few days, or they can enter this phase in short bursts of 5 to 10 seconds while standing, as birds do, says Manger.

Alternatively, like whales and dolphins, they may not need REM at all. Bigger animals generally tend to sleep less, probably because they have to spend so much time eating. But even among large mammals, elephants seem to be light sleepers. The considerably larger grey whale sleeps for 9 hours a day and the giraffe for almost 5 hours.

The domestic horse, at nearly 3 hours, is its closest rival.